Method and application unit for applying a sound-absorbing material in an inner cavity of a pneumatic tire

ABSTRACT

Method and application unit (3) for applying a sound-absorbing material (2) to an inner cavity of a pneumatic tyre (1) using a strip (4) of sound-absorbing material (2) provided on one side with an adhesive layer (6) covered with a protective lining (7). The following steps are provided: attaching an initial part of the protective lining (7) to a recovery drum (26); partially winding the strip of sound-absorbing material onto the applicator roller (24); pressing, by means of the applicator roller (24), the strip (4) of sound-absorbing material (2) against the inner cavity of the pneumatic tyre (1) whilst the pneumatic tyre (1) is caused to rotate; and rotating the recovery drum (26) synchronously with the pneumatic tyre (1), such as to wind the protective lining (7) around the recovery drum (26), step-by-step, as the protective lining (7) is separated from the strip (4) of sound-absorbing material (2).

TECHNICAL SECTOR

The present invention relates to a method and application unit forapplying a sound-absorbing material in an inner cavity of a pneumatictire.

PRIOR ART

As it is known, a pneumatic tire comprises a toroidal carcass, which hastwo annular beads and supports an annular tread. Between the carcass andthe tread, a tread belt is interposed which is provided with a number oftread plies. Within the carcass ply, an innerliner is arranged which isairtight, constitutes an inner lining and has the function of retainingthe air within the pneumatic tire in order to maintain the inflationpressure of the pneumatic tire itself over time.

In recent years the development of pneumatic tires has been directedtowards pneumatic tires that are internally provided with asound-absorbing material (generally a sponge) for reducing the noisegenerated by a pneumatic tire rolling on a road surface.

The sound-absorbing material is applied to a pneumatic tire that hasalready been vulcanized (inasmuch as the sound absorbing material wouldnot be able to withstand, without being damaged, the combination of heatand pressure that is applied during the vulcanization process), and inparticular it is glued to the inner surface of the pneumatic tire(comprising the innerliner) at the tread (i.e., corresponding to thearea of the pneumatic tire that comes into contact with the asphalt) andpossibly also at part of the side walls.

The sound-absorbing material is provided with an adhesive layer that isapplied to the surface that is intended to contact with the inner cavityof the pneumatic tire and is initially covered (protected) with aremovable protective lining (“liner”) that serves the function of bothprotecting the adhesive layer, and the function of making it possible towind the sound absorbing material into a coil without thesound-absorbing material sticking to itself.

Typically, the process for the application of the sound-absorbingmaterial inside the inner cavity of a pneumatic tire provides forstarting with a strip of sound-absorbing material (possibly wound into acoil) of a standard length that is more than required; it is thennecessary, initially, to cut the strip of sound-absorbing material inorder to eliminate the excess part and thereby confer to the strip ofsound-absorbing material the length required depending upon the innercircumference of the pneumatic tire whereupon the strip ofsound-absorbing material is to be glued; in other words, it isnecessary, initially, to cut the strip of acoustic material to size.After being cut to size, the strip of sound-absorbing material is woundonto itself such as to form a coil.

In practice an operator loads the coil of the strip of sound-absorbingmaterial that has been cut to size into an applicator device comprisingan applicator roller that is configured in order to press, after theremoval of the protective lining (which occurs a moment before pressingthe sound-absorbing material against the inner surface), thesound-absorbing material against the inner surface of the pneumatictyre; furthermore, the applicator device comprises a protective liningrecovery drum whereupon the same protective lining is wound after beingseparated from the sound-absorbing material (i.e. after having completedits function). The applicator roller and the recovery drum are providedwith actuating means that are suitable for bringing the same intorotation around the respective axis of rotation thereof, at appropriateand synchronous speeds, in such a way as to prevent the protectivelining and/or the sound-absorbing material from tearing due to excessivetension or being too loose.

When the operator loads the strip of sound-absorbing material into theapplicator device, the operator has to manually separate, from thesound-absorbing material, an initial part of the protective lining,which has to then be inserted (again manually) into a slot in therecovery drum. During the application of sound-absorbing material, it ispreferable to separate the protective lining from the sound-absorbingmaterial just before the application thereof in such a way as to leavethe adhesive exposed to air for as short a period of time as possible,in order to prevent foreign objects (debris, dust, dirt, insects . . . )from accidentally adhering to the adhesive layer.

In the meantime, the previously vulcanized pneumatic tire is supportedupon motorized rollers that cause it to rotate and that are providedwith fixed side rails that prevent any lateral translation of thepneumatic tire itself. In response to an operator command, an applicatordevice is inserted into the pneumatic tire, carried by the motorizedrollers, that presses a leading end of the strip of sound-absorbingmaterial against the inner surface of the pneumatic tire; the pneumatictire is then dragged into rotation by the motorized rollers in order tomake it possible to apply the sound-absorbing material over the entireinner surface (i.e., making a full turn and thereby imparting an annularshape to the sound-absorbing material).

The method described above for the application of sound-absorbingmaterial within a pneumatic tire inevitably requires the manualintervention of an operator in order to separate the initial part of theprotective lining from the sound-absorbing material; moreover, thisoperation is particularly long and complicated, even for an experiencedoperator, and can result in damage to the adhesive layer.

Furthermore, it is important that, during the application within thecavity, the sound-absorbing material does not undergo elongations orcompressions which, after a few thousand kilometers of use of thepneumatic tire, may lead to cracks within the sound-absorbing materialitself.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a method and anapplication unit for applying a sound-absorbing material within an innercavity of a pneumatic tire, which method and application unit make itpossible to render the entire application cycle more efficient (i.e.quicker and less expensive) and also more effective (i.e. capable ofavoiding damage to the adhesive layer during the separation of theinitial part of the protective lining from the sound-absorbingmaterial).

According to the present invention a method and an application unit areprovided for applying a sound-absorbing material inside an inner cavityof a pneumatic tire, according to that set forth in the attached claims.

The claims describe preferred embodiments of the present inventionforming an integral part of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to theattached drawings, which show an exemplary, non-limiting embodiment,wherein:

FIG. 1 is a schematic view of a pneumatic tire provided withsound-absorbing material arranged inside an inner cavity of a pneumatictire;

FIG. 2 is a schematic view of an application unit for applying asound-absorbing material within an inner cavity of a pneumatic tire;

FIGS. 3, 4 and 5 are multiple views at different instants of operationof a separation station of the application unit of FIG. 2 , wherein anexcess end is separated from a strip of sound-absorbing material; and

FIGS. 6-10 are multiple views at different instants of operation of acoupling station of the application unit of FIG. 2 wherein a strip ofsound-absorbing material is applied to an inner cavity of a pneumatictire.

PREFERRED EMBODIMENTS OF THE INVENTION

In FIG. 1 , the numeral 1 denotes, in the entirety thereof, a pneumatictire that is mounted on a rim and that is provided with a toroidalcarcass having two annular beads and that supports an annular tread.Between the carcass and the tread, a tread belt is interposed whichcomprises a number of tread plies. Inside the carcass ply, an innerlineris arranged which is airtight, constitutes an inner lining and has thefunction of retaining the air within the pneumatic tire_in order tomaintain the inflation pressure of the pneumatic tire itself over time.Within the inner cavity of the pneumatic tire1, i.e., in contact withthe inner surface of the pneumatic tire 1 comprising the innerliner, aloop of sound absorbing material 2 is affixed (generally a sponge) toreduce the noise generated by the rolling of the pneumatic tire upon theroad surface.

The sound-absorbing material 2 is applied to a pneumatic tire 1 that hasalready been vulcanized (inasmuch as the sound absorbing material 2would not be able to withstand, without being damaged, the combinationof heat and pressure that is applied during the vulcanization process),and in particular it is glued to the inner surface of the pneumatic tire1 (comprising the innerliner) at the tread (i.e, corresponding to thearea of the pneumatic tire that contacts with the asphalt) and possibly(but not necessarily) also at part of the side walls.

In FIG. 2 , indicated in the entirety thereof with the number 3 is anapplication unit that is suitable for applying the sound-absorbingmaterial 2, having an annular form, to the inner cavity of the pneumatictire 1. The application unit 3 comprises a separation station S1,wherein an excess end 5 (illustrated in FIGS. 4 and 5 ) is separatedfrom a strip 4 of sound-absorbing material 2 and a coupling station S2,wherein the strip 4 of sound-absorbing material 2 (deprived of theexcess end 5) is applied to the inner cavity of the pneumatic tire 1.

In particular, the strip 4 of sound-absorbing material 2, initially, hasa standard length that, depending upon the inner circumference of theinner cavity of the pneumatic tire 1, is greater than the requiredlength, and therefore, initially, it is necessary to cut it to size,removing from the strip 4 of sound-absorbing material 2 the excess end 5in such a way as to confer to the same strip 4 of sound-absorbingmaterial 2 the required length (calculated as a function of the innercircumference of the pneumatic tire 1).

As illustrated in FIGS. 3, 4 and 5 , the strip 4 of sound-absorbingmaterial 2 is provided on one side with an adhesive layer 6 that isintended to connect the sound-absorbing material 2 to the inner surfaceof the pneumatic tire and that is covered by a protective lining 7(i.e., with a ribbon of plastic material that adheres in a removablemanner to the adhesive layer 6). That is to say that the adhesive layer6 is applied to the surface of the sound-absorbing material 2 that isintended to come into contact with the inner cavity of the pneumatictire 1 and that is initially covered (protected) with the removableprotective lining 7 that serves both the function of protecting theadhesive layer 6 and the function of making it possible to wind thestrip 4 of sound absorbing material 2 into a coil without the soundabsorbing material 2 sticking to itself.

As previously stated, initially, in the separation station S1 the strip4 of sound-absorbing material 2 is cut in such a way as to separate theexcess end 5 and to thereby confer the required length (in order toimplement, without overlapping, a loop of sound-absorbing material 2within the pneumatic tire 1) to the strip 4 of sound-absorbing material2; normally the strip 4 of sound-absorbing material 2 initially has alength that is only slightly longer than necessary, and therefore thecutting to size of the strip 4 of sound-absorbing material 2 involvesthe waste of only a small piece of sound-absorbing material 2 (i.e., theexcess end 5 is small in size, generally ranging from a few centimetersto a few tens of centimeters).

As illustrated in FIG. 5 , by means of the strip 4 of sound-absorbingmaterial 2 a separation opening 8 is formed that starts from theopposite side of the protective lining 7, ends at the protective lining7, which remains intact, and separates the excess end 5 from theremaining part of the strip 4 of 2 sound-absorbing material; in otherwords, the separation opening 8 involves the entire depth of thesound-absorbing material 2, separating the excess end 5 from theremaining part of the strip 4 of sound-absorbing material 2, and theseparation opening 8 does not involve the protective lining 7 whichremains intact, constituting a residual connection between the excessend 5 and the remaining part of the strip 4 of sound-absorbing material2.

As illustrated in FIGS. 3, 4 and 5 , the implementation of theseparation opening 8 anticipates cutting, starting from an opposite sideof the protective lining 7, the strip 4 of sound-absorbing material 2,leaving intact a residual portion 9 of the sound-absorbing material 2(illustrated in FIG. 4 ) in the vicinity of the protective lining 7; theresidual portion 9 of the sound-absorbing material 2 is then fracturedby bending the excess end 5 in relation to the remaining part of thestrip 4 of sound-absorbing material 2 in order to complete theseparation opening 8 (as illustrated in FIG. 5 ).

According to a preferred embodiment, the residual portion 9 of thesound-absorbing material 2 is cooled such as to allow for cleanfracturing of the residual portion 9 by means of bending. That is tosay, in order be able to break the residual portion 9 of thesound-absorbing material 2 by bending it, it is necessary for theresidual portion 9 to be sufficiently fragile, i.e., insufficientlyelastic; in order to make the residual portion 9 sufficiently fragile,the same residual portion 9 is cooled to a (suitably) brittle state bycooling the sound-absorbing material 2 to close to the glass transitiontemperature (determined according to the ISO 11357-2 standard).Consequently, the residual portion 9 of the sound-absorbing material 2is cooled to temperatures no higher than 10° C. in relation to the glasstransition temperature (determined according to the ISO 11357-2standard) of the sound absorbing material 2 and preferably cooled totemperatures that are 5° C. lower than the glass transition temperature(determined according to the ISO 11357-2 standard). The cooling of thesound-absorbing material 2 can be performed in blowing a low temperaturecryogen gas 10 against the residual portion 9, dipping thesound-absorbing material 2 into a cryogenic liquid (bath), or placing(passing) the sound-absorbing material 2 within a cooling chamber thatis partially open at both ends. The working temperature of the coolingsystem depends upon the glass transition temperature (determinedaccording to the ISO 11357-2 standard) of the sound-absorbing material 2and must be such as to confer to the sound-absorbing material 2, whichconstitutes the residual portion 9, sufficient brittleness for it tobreak when bent.

According to a different embodiment, not illustrated, the separationopening 8 is not implemented in part by means of mechanical cutting(i.e., using a sharp instrument) and in part by breaking it when bent,but is fully implemented by means of laser cutting; in fact, simplemechanical cutting (i.e., using a sharp instrument) may not providesufficient accuracy in order to completely cut the sound-absorbingmaterial 2 whilst leaving intact the protective lining 7, whilst lasercutting could ensure such sufficient accuracy (also because a lasermight etch the sound-absorbing material 2 in a better way and theprotective lining 7 in a worse way). As an alternative to laser cutting,water-cutting may be used (which might etch the sound-absorbing material2 in a better way and the protective lining 7 in a worse way), or elseultrasonic cutting could be used (which might etch the sound-absorbingmaterial 2 in a better way and the protective lining 7 in a worse way).

The separation station S1 comprises a support plane 11 having a portion12 whereupon the strip 4 of sound-absorbing material 2 rests and aportion 13 whereupon the excess end 5 rests and which is hinged to thepart 12 in order to rotate in relation to the part 12 around an axis ofrotation 14 (illustrated in FIG. 3) arranged at the separation opening8. According to a preferred embodiment, the part 13 of the support plane11 is kept parallel to the part 12 of the support plane 11 by means ofan elastic element 15 (for example, a helical spring, illustrated inFIG. 4 ); the separation station S1 comprises a pusher 16 (driven by anactuator device 17) that by pressing against the excess end 5 leads tothe rotation of the part 13 of the support plane 11 in relation to thepart 12 of the support plane 11 around the axis 14 of rotation in such away as to bend the strip 4 of sound-absorbing material 2, and therebydetermine the brittle fracturing of the residual portion 9.

At the axis 14 of rotation (i.e., at the boundary between the two parts12 and 13 of the support plane 11 wherein the separation opening 8 islocated), a nozzle 18 is arranged which is oriented towards the supportplane 11, is connected to a reservoir containing the cryogen gas 10, andthat is suitable for emitting a jet of cryogen gas 10 which (mainly)impacts the residual portion 9 such as to freeze the same residualportion 9, thereby rendering it fragile.

According to a preferred embodiment, the pusher 16 initially pushesagainst the excess end 5 in order to rotate the excess end 5, moving itaway from the remaining part of the strip 4 of sound-absorbing material2 in such a way as to widen the separation opening 8, thereby exposingthe residual portion 9 to the nozzle 18; at this point, the pusher 16temporarily stops, the nozzle 18 emits a jet of cryogen gas 10, which(mainly) impacts the residual portion 9 (by now well exposed to thenozzle 18), and only when the jet of cryogen gas 10 ends does the pusher16 resume the movement thereof in order to further rotate the excess end5, thereby determining at this point the brittle fracturing of theresidual portion 9 that has been frozen. By way of example, the pusher16 may initially rotate the excess end 5 by 20-40° in order to exposethe residual portion 9 to the nozzle 18; subsequently, the pusher 16 maythen rotate the excess end 5 until it reaches 60-90° in order to resultin the brittle fracturing of the residual portion 9 that has beenfrozen.

In other words, initially, in the separation station S1, the excess end5 is bent in relation to the remaining part of the strip 4 ofsound-absorbing material 2 until it reaches a first bending angle (forexample equal to 20-40°) such as to widen the separation opening 8, thelow temperature cryogen gas 10 is blown against the residual portion 9,and finally the excess end 5 is bent further in relation to theremaining part of the strip 4 of sound-absorbing material 2 until itreaches a second bending angle (for example equal to 60-90°) greaterthan the first bending angle in order to break the residual portion 9.

As illustrated in FIGS. 3 and 4 , the separation station S1 comprises asharp instrument 19 (for example, a rotating circular blade) that isused to implement, by means of mechanical cutting, the initial part ofthe separation opening 8, or to cut the strip 4 of sound-absorbingmaterial 2 until reaching the residual portion 9.

As illustrated in FIG. 2 , once the strip 4 of sound-absorbing material2 has completed the processing cycle thereof in the separation stationS1 (i.e., when the separation opening 8 has been completed whichseparates the excess end 5 from the remaining part of the strip 4 ofsound-absorbing material 2, leaving intact the protective lining 7), thestrip 4 of sound-absorbing material 2 is wound on itself such as to forma coil (which terminates externally with the excess end 5) and is thentransferred (in more or less an automated manner) to the couplingstation S2.

The coupling station S2 comprises a support device that is suitable forsupporting and bringing into rotation, around a central axis thereof,the pneumatic tire 1. In particular, the support device 20 comprisesmotorized rollers whereupon the pneumatic tire 1 itself rests and siderails (not illustrated) that contain the pneumatic tire 1, preventingthe pneumatic tire 1 from performing any form of lateral translationduring the rotational movement thereof.

The coupling station S2 comprises an applicator device 21 that issuitable for applying the strip 4 of sound-absorbing material 2 to theinner surface of the pneumatic tire 1, progressively removing theprotective lining 7. That is to say, the applicator device 21progressively separates the protective lining 7 from the strip 4 ofsound-absorbing material 2 as the strip 4 of sound-absorbing material 2is applied to the inner cavity of the pneumatic tire 1; in particular,the applicator device 21 initially pulls the excess end 5 in relation tothe remaining part of the strip 4 of sound-absorbing material 2 such asto separate the protective lining 7 from the strip 4 of sound-absorbingmaterial 2, i.e., the applicator device 21 uses the excess end 5 as agripping point in order to begin to separate the protective lining 7from the strip 4 of sound-absorbing material 2.

The coupling station S2 comprises a movement device 22 that supports theapplicator device 21 and that is suitable for moving the applicatordevice 21 between a loading/unloading position wherein the applicatordevice 21 is separated from the pneumatic tire 1 (that is external tothe pneumatic tire 1) and a work position (illustrated in FIG. 2 )wherein the applicator device 21 is located within the pneumatic tire 1.In the loading/unloading position, a new strip 4 of sound-absorbingmaterial 2, wound into a coil, is loaded into the applicator device 21whilst only the previously applied protective lining 7 of a strip 4 ofsound-absorbing material 2 is unloaded (removed) from the applicatordevice 21. Conversely, in the working position (illustrated in FIG. 2 )a new strip 4 of sound-absorbing material 2, inserted into theapplicator device 21, is applied to the inner cavity of the pneumatictire 1.

According to that illustrated in FIGS. 6-10 , the applicator device 21comprises a housing 23 that is suitable for containing the strip 4 ofsound-absorbing material 2 wound into a coil, an applicator roller 24which, being mounted rotating around an axis of rotation 25, is suitablefor pressing the strip 4 of sound-absorbing material 2 against the innersurface of the pneumatic tire 1 in order to adhere the strip 4 ofsound-absorbing material 2 to the inner surface of the pneumatic tire 1,and a recovery roller 26 that is mounted rotating around an axis 27 ofrotation parallel to the axis 25 of rotation, and that is suitable forwinding the protective lining 7, step-by-step, such that the protectivelining 7 is separated from the strip 4 of sound-absorbing material 2. Inparticular, the housing 23 is arranged above the applicator roller 24and above the recovery drum 26. In other words, the applicator device 21comprises an applicator roller 24 that is configured to press thesound-absorbing material 2 against the inner surface of the pneumatictire 1, after the removal of the protective lining 7, which occurs amoment before pressing the sound-absorbing material 2 against the innersurface of the pneumatic tire 1; furthermore, the applicator device 21comprises a protective lining recovery drum 26, whereupon the sameprotective lining 7 is wound after being separated from thesound-absorbing material 2, i.e., after having completed its function.

During the application of the sound-absorbing material 2, it ispreferable to separate the protective lining 7 from the sound-absorbingmaterial 2, just before the application thereof, in such a way as toleave the layer 6 of adhesive exposed to air for as short a period oftime as possible, in order to prevent foreign objects (debris, dust,dirt, insects . . . ) from accidentally adhering to the adhesive layer.

The applicator roller 24 and the recovery drum 26 are provided withactuating means that are suitable for bringing them into rotation aroundthe respective axis 25 and 27 of rotation at appropriate and synchronousspeeds in such a way as to prevent the protective lining 7 and/or thesound-absorbing material 2 from tearing due to excessive tension orbeing too loose.

The recovery drum 26 is provided with a motorized grip member 28 (forexample a gripper provided with two opposing jaws) that is suitable forgrasping the excess end 5 of the strip 4 of sound-absorbing material 2that is wound into a coil and located in the housing 23; i.e., therecovery drum 26 supports the motorized grip member 28 that is suitablefor grasping the excess end 5 of the strip 4 of sound-absorbing material2.

The recovery drum 26 is mounted movable in the applicator device 21 inorder to move itself to different positions (illustrated in FIGS. 6-10 )along a circular trajectory (i.e., along an arc of circumference); i.e.,the recovery drum 26, other than being mounted rotating around thecentral axis 27 of rotation in order to rotate upon itself, it ispivotally mounted in order to rotate around a further axis 29 ofrotation that is parallel and eccentric (i.e., non-coaxial) in relationto the axis and 27 of rotation (i.e., in relation to the applicatorroller 24 and the recovery drum 26). In particular, an actuator device30 is provided that moves, as will be explained below, the recovery drum26, by rotating the recovery drum 26 about the axis 29 of rotation(i.e., causing the recovery drum 26 to complete a circular path).

The applicator device 21 comprises a presser roller 31 that is suitablefor pressing the strip 4 of sound-absorbing material 2 against theapplicator roller 24 and that is mounted idling at one end of an armthat is hinged such as to rotate around an axis 32 of rotation (parallelto the axis 25, 27 and 29 of rotation) under the control of an actuatordevice 33. In rotating around the axis 32 of rotation, the presserroller 31 is movable between a passive position (illustrated in FIGS. 6and 7 ) wherein the presser roller 31 is at a distance from theapplicator roller 24 and from the strip 4 of sound-absorbing material 2,and an active position (illustrated in FIGS. 8, 9 and 10 ) wherein thepresser roller 31 presses the strip 4 of sound-absorbing material 2against the applicator roller 24.

Whilst the applicator device 21 is located in the loading/unloadingposition (i.e., externally to the pneumatic tire 1), the strip 4 ofsound-absorbing material 2 is inserted, coiled, into the housing 23 ofthe applicator device 21, arranging the excess end 5 outside the housing23 and facing downwards. Subsequently, the motorized grip member 28 ofthe recovery drum 26 grasps the excess end 5, thereby rendering theexcess end 5 integral to the same recovery drum 26; during this step,the recovery drum 26 is arranged at an initial position (illustrated inFIG. 6 ) wherein the recovery drum 26 is arranged to the left of theapplicator drum 24 (i.e., from a first side of the applicator drum 24)and is facing an outlet of the housing 23.

Subsequently, the actuator device 30 moves the recovery drum 26, whichis holding the excess end 5, from the initial position (illustrated inFIG. 6 ) to an intermediate position (illustrated in FIG. 7 ) whereinthe recovery drum 26 is arranged to the right of the applicator drum 24(i.e., from a second side of the applicator drum 24 opposite the firstside) such as to partially wind the strip 4 of sound-absorbing material2 around the applicator roller 24. In other words, the actuator device30 moves the recovery drum 26, which is holding the excess end 5, fromthe first side of the applicator roller 24 to the second side of theapplicator roller 24 opposite the first side, such as to partially windthe strip 4 of sound-absorbing material 2 around the applicator roller24.

Subsequently and as illustrated in FIG. 8 , the actuator device 33 movesthe presser roller 31 from the passive position (illustrated in FIG. 7 )to the active position (illustrated in FIG. 8 ) such as to press thestrip 4 of sound-absorbing material 2 against the applicator roller 24.

Subsequently and as illustrated in FIG. 9 , the actuator device 30 movesthe recovery drum 26, which is holding the excess end 5, from theintermediate position (illustrated in FIGS. 7 and 8 ) to a finalposition (illustrated in FIG. 9 ) wherein the recovery drum 26 isarranged to the left of the applicator drum 24 (i.e., from the firstside of the applicator drum 24) such as to separate part of theprotective lining 7 from the strip 4 of sound-absorbing material 2. Inother words, the actuator device 30 moves the recovery drum 26, which isholding the excess end 5, from the second side of the applicator roller24 to the first side of the applicator roller 24, such as to separatepart of the protective lining 7 from the strip 4 of sound-absorbingmaterial 2. When the recovery drum 26 is moved from the intermediateposition (illustrated in FIGS. 7 and 8 ), which is located at the secondside of the applicator roller 24, to the final position (illustrated inFIGS. 9 and 10), which is located at the first side of the applicatorroller 24, the protective lining 7 is partially wound around therecovery drum 26.

Thus, the applicator device 21 is suitable for pulling the excess end 5in relation to the remaining part of the strip 4 of sound-absorbingmaterial 2 such as to separate the protective lining 7 from the strip 4of sound-absorbing material 2.

In particular, the final position (illustrated in FIG. 9 ) of therecovery drum 26 is different than the initial position (illustrated inFIG. 7 ) of the recovery drum 26, i.e., when the recovery drum 26 ismoved from the second side of the applicator roller 24 to the first sideof the applicator roller 24, then it is arranged in the final position(illustrated in FIG. 9 ), which is different in relation to the initialposition (illustrated in FIG. 6 ) that is assumed in order to grasp theexcess end 5 (i.e. to grasp the initial part of the protective lining7).

It should be noted that the recovery drum 26 is moved from theintermediate position (illustrated in FIGS. 7 and 8 ), which is locatedat the second side of the applicator roller 24, to the final position(illustrated in FIGS. 9 and 10 ), which is located at the first side ofthe applicator roller 24, before inserting the applicator device 21(comprising the applicator roller 24 and the recovery drum 26) into thepneumatic tire 1.

At this point and as illustrated in FIG. 10 , the movement device 22moves the applicator device 21 between the loading/unloading position(assumed in FIGS. 6-9 ), wherein the applicator device 21 is separatedfrom, and external to, the pneumatic tire 1, and the working position(illustrated in FIGS. 2 and 10 ) wherein the applicator device 21 islocated inside the pneumatic tire_1. In the work position (illustratedin FIGS. 2 and 10 ), the applicator roller 24 presses the strip 4 ofsound-absorbing material 2 against the inner cavity of the pneumatictire 1, whilst the pneumatic tire 1 is caused to rotate and,simultaneously, the recovery drum 26 is rotated synchronously with thepneumatic tyre 1, such as to wind the protective lining 7 around therecovery drum 26, step-by-step, as the protective lining 7 is separatedfrom the strip 4 of sound-absorbing material 2.

In other words, the applicator device 21, when it is in the workingposition within the pneumatic tire 4, is configured to progressivelyseparate the protective lining 7 from the strip 4 of sound-absorbingmaterial 2, step-by-step, as the strip 4 of sound-absorbing material 2is applied to the inner cavity of the pneumatic tire 1.

According to a preferred embodiment, the presser roller 31 moves awayfrom the strip 4 of sound-absorbing material 2 before commencing withthe rotation of the pneumatic tire 1; i.e., the actuator device 33 movesthe presser roller 31 from the active position (illustrated in FIGS. 8,9 and 10 ) to the passive position (illustrated in FIGS. 6 and 7 )before commencing with the rotation of the pneumatic tire 1.

The embodiments described herein may be combined without departing fromthe scope of protection of the present invention.

The application unit 3 described above has many advantages.

In the first place, the application unit 3 described above makes itpossible to fully automate the processing cycle, also as regards theseparation of the initial part of the protective lining 7 from thesound-absorbing material 2; this result is obtained by virtue of thefact that the initial part of the protective lining 7 can be grasped ingripping the excess end 5 which can easily be grasped, also in anautomated manner (being of considerable size and substantiallydisconnected from the remaining part of the strip 4 of sound-absorbingmaterial 2).

Furthermore, the application unit 3 described above makes it possible torender the whole application cycle more efficient (i.e., quicker andless expensive, especially by virtue of the possibility of completeautomation) and also more effective (i.e., capable of ensuring highquality of application such to avert any damage to the sound-absorbingmaterial 2).

In particular, the application unit 3 described above ensures that,during the application within the inner cavity of the pneumatic tire 1,the sound-absorbing material 2 does not undergo elongations orcompressions which, after a few thousand kilometers of use of thepneumatic tire 1, may lead to cracks within the same sound-absorbingmaterial 2.

1-10. (canceled)
 11. A method of applying a sound-absorbing material toan inner cavity of a pneumatic tire using a strip of sound-absorbingmaterial provided on one side with an adhesive layer covered with aprotective lining, the method comprising: using a grip member that isintegral to a recovery drum, grasping an initial part of the protectivelining whilst the recovery drum is at a first side of an applicatorroller; moving the recovery drum, which is holding the initial part,from the first side of the applicator roller to a second side of theapplicator roller, opposite the first side, such as to partially windthe strip of sound-absorbing material around the applicator roller;pressing, via the applicator roller, the strip of sound-absorbingmaterial against the inner cavity of the pneumatic tire whilst thepneumatic tire is caused to rotate; and rotating the recovery drumsynchronously with the pneumatic tire to wind the protective liningaround the recovery drum, step-by-step, as the protective lining isseparated from the strip of sound-absorbing material.
 12. The method ofclaim 11, further comprising: pressing the strip of sound-absorbingmaterial against the applicator roller using a presser roller; andmoving the recovery drum, which is holding the initial part, from thesecond side of the applicator roller to the first side of the applicatorroller to separate part of the protective lining from the strip ofsound-absorbing material.
 13. The method of claim 12, wherein therecovery drum is moved from the second side of the applicator roller tothe first side of the applicator roller before inserting the applicatordevice and the recovery drum into the pneumatic tire.
 14. The method ofclaim 12, wherein, when the recovery drum is moved from the second sideof the applicator roller to the first side of the applicator roller, theprotective lining is partially wound onto the recovery drum.
 15. Themethod of claim 12, wherein, when the recovery drum is moved from thesecond side of the applicator roller to the first side of the applicatorroller, it is arranged in a position that is different in relation to aninitial position that was assumed to grasp the initial part of theprotective lining.
 16. The method of claim 12, wherein the presserroller is moved away from the strip of sound-absorbing material beforecommencing with the rotation of the same pneumatic tire.
 17. The methodof claim 11, comprising: implementing, via the strip of sound-absorbingmaterial, a separation opening that starts from an opposite side of theprotective lining and ends at the protective lining that remains intactand separates an excess end with respect to a required length from aremaining part of the strip of sound-absorbing material; and graspingthe excess end using the grip member, which is integral to the recoverydrum, to attach the initial part of the protective lining to therecovery drum.
 18. The method of claim 11, wherein the recovery drum ismounted rotating around a second axis of rotation that is parallel andeccentric to the applicator roller.
 19. The method of claim 11, whereinthe strip of sound-absorbing material is wound such as to form a coiland is located within a housing arranged above the applicator roller andabove the recovery drum.
 20. An application unit for applying asound-absorbing material in an inner cavity of a pneumatic tire using astrip of sound-absorbing material provided on one side with an adhesivelayer covered with a protective lining, the application unit comprising:a recovery drum having a gripping member integral thereto and configuredto grasp an initial part of the protective lining whilst the recoverydrum is located at a first side of an applicator roller; the applicatorroller, around which the strip of sound-absorbing material is partiallywound; a first actuator device that is configured to press, using theapplicator roller, the strip of sound-absorbing material against theinner cavity of the pneumatic tire whilst the pneumatic tire is causedto rotate; a second actuator device that is configured to rotate therecovery drum synchronously with the pneumatic tire to wind theprotective lining around the recovery drum, step-by-step, as theprotective lining is separated from the strip of sound-absorbingmaterial; and a third actuator device configured to move the recoverydrum, which is holding the initial part, from the first side of theapplicator roller to a second side of the applicator roller, oppositethe first side, to partially wind the strip of sound-absorbing materialaround the applicator roller.
 21. The application unit of claim 20,wherein the third actuator device is configured to move the recoverydrum from the second side of the applicator roller to the first side ofthe applicator roller before the applicator device and the recovery drumare inserted into the pneumatic tire.
 22. The application unit of claim21, wherein, when the recovery drum is moved from the second side of theapplicator roller to the first side of the applicator roller, theprotective lining is partially wound onto the recovery drum.
 23. Theapplication unit of claim 21, wherein, when the recovery drum is movedfrom the second side of the applicator roller to the first side of theapplicator roller, it is arranged in a position that is different inrelation to an initial position that was assumed to grasp the initialpart of the protective lining.
 24. The application unit of claim 21,wherein the applicator roller is moved away from the strip ofsound-absorbing material before commencing with the rotation of the samepneumatic tire.
 25. The application unit of claim 20, wherein therecovery drum is mounted rotating around a second axis of rotation thatis parallel and eccentric to the applicator roller.
 26. The applicationunit of claim 20, wherein the strip of sound-absorbing material is woundsuch as to form a coil and is located within a housing arranged abovethe applicator roller and above the recovery drum.